Combustor cap assembly having impingement plate with cooling tubes

ABSTRACT

A combustor cap assembly, combustor and related method are disclosed. The combustor cap assembly includes: an impingement plate defining a plurality of impingement cooling holes with a first side of the impingement plate in fluid communication with a cooling air plenum. The assembly also includes a combustor cap plate coupled to the impingement plate, such that an impingement air plenum is defined between a second side of the impingement plate and the combustor cap plate. Tubes extend from at least a portion of the plurality of impingement cooling holes at the second side of the impingement plate and extend partially towards the combustor cap plate through the impingement air plenum. The plurality of impingement cooling holes provides for fluid communication between the cooling air plenum and the impingement air plenum through the tubes.

TECHNICAL FIELD

The disclosure relates generally to turbomachinery and, moreparticularly, to a combustor cap assembly impingement plate includingcooling tubes for directing coolant to an upstream side of a cap plate.

BACKGROUND

In an air-ingesting turbomachine (e.g., a gas turbine), air enters acompressor and is progressively pressurized as it is routed towards acombustor. The compressed air is premixed with a fuel and ignited withina reaction zone defined within a combustor liner, thus producing hightemperature combustion gases. The combustion gases are then routed fromthe combustion chamber via the liner and/or a transition piece into aturbine section of the turbomachine where the combustion gases flowacross alternating rows of stationary vanes and rotor blades, the latterof which are secured to a rotor shaft. As the combustion gases flowacross the rotor blades, kinetic and/or thermal energy are transferredto the rotor blades, thus causing the rotor shaft to rotate.

To increase turbine efficiency, modern combustors are operated at hightemperatures, which generate high thermal stresses on various mechanicalcomponents disposed within the combustor. As a result, at least aportion of the compressed air supplied to the combustor is used ascooling air to cool these components. For example, particular combustorsinclude a generally annular combustor cap assembly that at leastpartially surrounds one or more fuel nozzles within the combustor.Certain combustor cap assembly designs include a cap plate that isdisposed at a downstream end of the combustor cap assembly. The fuelnozzles extend at least partially through the cap plate, which istypically disposed substantially adjacent to the combustion chamber. Asa result, the cap plate is generally exposed to extremely hightemperatures.

One way to cool the cap plate is to route a portion of a coolant, suchas compressed, cooling air, into the combustor cap assembly and onto anupstream side of the cap plate. The coolant is directed to the upstreamside of the cap plate by an impingement plate that includes a number ofholes therein. The impingement plate and the cap plate form animpingement air plenum therebetween. Current impingement plates may alsoinclude cooling flow return passages that route the coolant from theimpingement cooling plenum upstream of the cap plate to cool other partsof the combustor. One challenge with cooling this form of combustor capassembly is that the cooling air may be re-directed away from the capplate prior to it impinging on the upstream side of the cap plate, thusreducing its cooling effectiveness on the cap plate.

BRIEF DESCRIPTION

An aspect of the disclosure provides a combustor cap assembly,comprising: an impingement plate defining a plurality of impingementcooling holes, wherein a first side of the impingement plate is in fluidcommunication with a cooling air plenum; a combustor cap plate coupledto the impingement plate, wherein the combustor cap plate and a secondside of the impingement plate define an impingement air plenumtherebetween; and tubes extending from at least a portion of theplurality of impingement cooling holes at the second side of theimpingement plate and extending partially towards the combustor capplate through the impingement air plenum; wherein the plurality ofimpingement cooling holes provides for fluid communication between thecooling air plenum and the impingement air plenum through the tubes.

Another aspect of the disclosure provides a combustor, comprising: acombustor cap assembly including: an impingement plate defining aplurality of impingement cooling holes, wherein a first side of theimpingement plate is in fluid communication with a cooling air plenum; acap plate coupled to the impingement plate, wherein the cap plate and asecond side of the impingement plate define an impingement air plenumtherebetween; and tubes extending from at least a portion of theplurality of impingement cooling holes at the second side of theimpingement plate and extending partially towards the cap plate throughthe impingement air plenum; wherein the plurality of impingement coolingholes provides for fluid communication between the cooling air plenumand the impingement air plenum through the tubes; and a fuel nozzleextending through the combustor cap assembly.

An aspect of the disclosure provides a method comprising: communicatinga cooling air flow from a cooling air plenum through an impingementplate defining a plurality of impingement cooling holes therein, whereina first side of the impingement plate is in fluid communication with thecooling air plenum; and directing the cooling air flow through tubesextending from at least a portion of the plurality of impingementcooling holes at a second side of the impingement plate toward acombustor cap plate.

Yet another aspect includes an insert for an impingement plate includinga plurality of cooling holes therein, the insert comprising: a bodyincluding: an opening extending longitudinally therethrough; a dischargeend configured for positioning in an impingement air plenum between theimpingement plate and an upstream surface of a combustor cap plate; aflexible insertion end configured for insertion into a respectivecooling hole of the plurality of cooling holes; and a fixation elementbetween the discharge end and the flexible insertion end, the fixationelement having a first outer dimension configured to fixedly couple thebody in the respective cooling hole.

Another aspect relates to an impingement plate for a combustor capassembly, comprising: a first body defining a plurality of impingementcooling holes, wherein a first side of the first body is configured tobe positioned in fluid communication with a cooling air plenum and asecond side of the first body is configured to connect in a spacedmanner to a combustor cap plate, the second side of the first body andthe combustor cap plate defining an impingement air plenum therebetween;and tubes extending from at least a portion of the plurality ofimpingement cooling holes at the second side of the impingement plate.

The illustrative aspects of the present disclosure are designed to solvethe problems herein described and/or other problems not discussed.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of this disclosure will be more readilyunderstood from the following detailed description of the variousaspects of the disclosure taken in conjunction with the accompanyingdrawings that depict various embodiments of the disclosure, in which:

FIG. 1 is a schematic diagram of an illustrative turbomachine in theform of a gas turbine that may incorporate at least one embodiment ofthe disclosure;

FIG. 2 is a cross-sectional side view of a portion of an illustrativecombustion section in which teachings of the disclosure may be employed;

FIG. 3 is a cross-sectional perspective view of a portion of anillustrative combustor cap assembly, according to one or moreembodiments of the disclosure;

FIG. 4 is an enlarged partial cross-sectional view of a combustor capassembly with cooling tube inserts, according to one or more embodimentsof the disclosure;

FIG. 5 is a plan view of a combustor cap plate according to embodimentsof the disclosure;

FIG. 6 is an enlarged partial cross-sectional view of a combustor capassembly with integral cooling tubes, according to one or moreembodiments of the disclosure;

FIG. 7 shows a side view of a cooling tube insert, according toembodiments of the disclosure;

FIG. 8 shows an enlarged cross-sectional view of a cooling tube insertin an impingement plate, according to embodiments of the disclosure;

FIG. 9 shows an enlarged cross-sectional view of a cooling tube insertbeing inserted in an impingement plate, according to embodiments of thedisclosure; and

FIG. 10 shows an enlarged cross-sectional view of a cooling tube insertinserted in an impingement plate, according to alternative embodimentsof the disclosure.

It is noted that the drawings of the disclosure are not necessarily toscale. The drawings are intended to depict only typical aspects of thedisclosure, and therefore should not be considered as limiting the scopeof the disclosure. In the drawings, like numbering represents likeelements between the drawings.

DETAILED DESCRIPTION

As an initial matter, in order to clearly describe the currenttechnology, it will become necessary to select certain terminology whenreferring to and describing relevant machine components within aturbomachine, or a combustor section thereof. To the extent possible,common industry terminology will be used and employed in a mannerconsistent with its accepted meaning. Unless otherwise stated, suchterminology should be given a broad interpretation consistent with thecontext of the present application and the scope of the appended claims.Those of ordinary skill in the art will appreciate that often aparticular component may be referred to using several different oroverlapping terms. What may be described herein as being a single partmay include and be referenced in another context as consisting ofmultiple components. Alternatively, what may be described hereinincluding multiple components may be referred to elsewhere as a singlepart.

In addition, several descriptive terms may be used regularly herein, andit should prove helpful to define these terms at the onset of thissection. These terms and their definitions, unless stated otherwise, areas follows. As used herein, “downstream” and “upstream” are terms thatindicate a direction relative to the flow of a fluid, such as theworking fluid through the turbine engine or, for example, the flow ofair through the combustor or coolant through one of the combustionsection's components. The term “downstream” corresponds to the directionof flow of the fluid, and the term “upstream” refers to the directionopposite to the flow. As used herein, the flow of fluid is that of thecooling air flow. The terms “forward” and “aft,” without any furtherspecificity, refer to directions, with “forward” referring to the frontor compressor end of the engine (or the inlet end of the combustor), and“aft” referring to the rearward or turbine end of the engine (or theoutlet end of the combustor).

It is often required to describe parts that are disposed at differingradial positions with regard to a center axis. The term “radial” refersto movement or position perpendicular to an axis. For example, if afirst component resides closer to the axis than a second component, itwill be stated herein that the first component is “radially inward” or“inboard” of the second component. If, on the other hand, the firstcomponent resides further from the axis than the second component, itmay be stated herein that the first component is “radially outward” or“outboard” of the second component. The term “axial” refers to movementor position parallel to an axis. Finally, the term “circumferential”refers to movement or position around an axis. It will be appreciatedthat such terms may be applied in relation to the center axis of thecombustor, described herein.

In addition, several descriptive terms may be used regularly herein, asdescribed below. The terms “first”, “second”, and “third” may be usedinterchangeably to distinguish one component from another and are notintended to signify location or importance of the individual components.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components but do not preclude the presence or addition of one ormore other features, integers, steps, operations, elements, components,and/or groups thereof. “Optional” or “optionally” means that thesubsequently described event or circumstance may or may not occur orthat the subsequently described component or feature may or may not bepresent, and that the description includes instances where the eventoccurs or the component is present and instances where it does not occuror is not present.

Where an element or layer is referred to as being “on,” “engaged to,”“coupled to” or “connected to” another element or layer, it may bedirectly on, engaged to, coupled to, or connected to the other elementor layer, or intervening elements or layers may be present. In contrast,when an element is referred to as being “directly on,” “directly engagedto,” “directly coupled to” or “directly connected to” another element orlayer, there may be no intervening elements or layers present. Otherwords used to describe the relationship between elements should beinterpreted in a like fashion (e.g., “between” versus “directlybetween,” “adjacent” versus “directly adjacent,” etc.). As used herein,the term “and/or” includes any and all combinations of one or more ofthe associated listed items.

As indicated above, the disclosure provides an impingement plate havingcooling tubes therein that deliver cooling air closer to an upstreamside of a combustor cap plate. A combustor cap assembly and combustorincluding the impingement plate are also provided. Inserts to create thecooling tubes in an impingement plate and a related method are alsodescribed herein. The tubes, which may extend from any number of aplurality of impingement cooling holes at the side of the impingementplate next to the combustor cap plate, extend partially towards thecombustor cap plate through an impingement air plenum between theimpingement plate and the combustor cap plate. The plurality ofimpingement cooling holes provides for fluid communication between thecooling air plenum and the impingement air plenum through the tubes. Thecooling tubes prevent the cooling air from being prematurely re-directedaway from the combustor cap plate prior to it impinging on the upstreamside of the combustor cap plate, thus improving cooling of the capplate.

As will be described, the cooling tubes may be integrally formed withthe impingement plate, e.g., via additive manufacture or casting, orinserts for the cooling holes can create the cooling tubes for theimpingement plate. The inserts may include a body having a discharge endconfigured for positioning in an impingement air plenum between theimpingement plate and an upstream surface of a combustor cap plate, anda flexible insertion end configured for insertion into a respectivecooling hole in the impingement plate. A fixation element between thedischarge end and the flexible insertion end has an outer dimensionconfigured to fixedly couple the body in the respective cooling hole.

FIG. 1 provides a functional block diagram of an illustrative gasturbine system 10 (“GT system” 10) that may incorporate variousembodiments of the disclosure. As shown, GT system 10 generally includesan inlet section 12 that may include a series of filters, cooling coils,moisture separators, and/or other devices to purify and otherwisecondition a working fluid, such as air 14, entering GT system 10. Air 14flows to a compressor section where a compressor 16 progressivelyimparts kinetic energy to air 14 to produce a compressed or pressurizedair 18 (sometimes also referred to herein as “air 18” or “cooling air18”).

Compressed air 18 is mixed with a fuel 20 from a fuel source 22 to forma combustible mixture within one or more combustors 24. The combustiblemixture is burned to produce combustion gases 26 having a hightemperature, pressure and velocity. Combustion gases 26 flow through aturbine 28 of a turbine section to produce work. For example, turbine 28may be coupled to a shaft 30 so that rotation of turbine 28 drivescompressor 16 to produce compressed air 18. Alternatively, or inaddition, shaft 30 may connect turbine 28 to a generator 32 forproducing electricity. Exhaust gases 34 from turbine 28 flow through anexhaust section 36 that connects turbine 28 to an exhaust stack 38downstream from turbine 28. Exhaust section 36 may include, for example,a heat recovery steam generator (not shown) for cleaning and extractingadditional heat from exhaust gases 34 prior to release to theenvironment.

FIG. 2 is a cross-sectional side view of a portion of an illustrativecombustor 24 according to one or more embodiments of the disclosure. Asshown in FIG. 2, combustor 24 is at least partially surrounded by atleast one outer casing 40, such as a compressor discharge casing. Outercasing 40 is in fluid communication with compressor 16 (FIG. 1) so as toreceive at least a portion of compressed air 18 therefrom.

As shown in FIG. 2, an end cover 42 is coupled to outer casing 40 toprovide a seal around an opening defined within outer casing 40. Theopening is generally sized for receiving combustor 24. Outer casing 40(and/or end cover 42) at least partially defines a high pressure plenum44, which at least partially surrounds combustor 24. A head end portion46 of combustor 24 is at least partially defined by end cover 42 andouter casing 40. Head end portion 46 defines an area within combustor 24where a portion of compressed air 18 from high pressure plenum 44reverses flow direction.

At least one fuel nozzle 48 extends substantially axially within outercasing 40 with respect to an axial centerline of combustor 24 and/or anaxial centerline of end cover 42. As shown in FIG. 2, combustor 24 mayinclude a plurality of fuel nozzles 48 extending axially within head endportion 46. Fuel nozzle 48 may be coupled at a first end to end cover42. A second or downstream end of fuel nozzle 48 terminates proximate toa combustion chamber or zone 50 defined within a combustion liner 52,which extends downstream from fuel nozzle 48. As will be described, fuelnozzle(s) 48 extend into a combustor cap assembly 100.

Combustion liner 52 may at least partially define an annular flowpassage 54 within outer casing 40. In particular embodiments, annularflow passage 54 may be defined or further defined by one or more of animpingement sleeve or liner 56, which surrounds combustion liner 52. Inparticular embodiments, annular flow passage 54 may be defined orfurther defined by any one or more of outer casing 40, end cover 42and/or other liners or features, such as an inner wall provided withinouter casing 40. Annular passage 54 provides for fluid communicationbetween high pressure plenum 44 and head end portion 46 of combustor 24.

In various embodiments, combustor cap assembly 100 extends radially,circumferentially and axially within a forward, or upstream, end ofliner 42. In one embodiment, combustor cap assembly 100 includes anannularly shaped flow conditioning plate 102 and an annularly shapedshroud 104. In particular embodiments, combustor cap assembly 100 mayinclude an annularly shaped secondary shroud 106, which extends from aforward end portion 108 of flow conditioning plate 102 towards end cover42. Shroud 104 and/or secondary shroud 106 may be coaxially aligned withflow conditioning plate 102.

As shown in FIG. 2, flow conditioning plate 102, shroud 104 and/orsecondary shroud 106 circumferentially surround at least a portion offuel nozzle(s) 48. In one embodiment, as shown in FIG. 2, flowconditioning plate 102 and shroud 104 at least partially define acooling air plenum 110 around fuel nozzle 48 within combustor capassembly 100. In other embodiments, cooling air plenum 110 may befurther defined by secondary shroud 106. Cooling air plenum 110 is influid communication with head end portion 46 of combustor 24, which, asstated, is in fluid communication with high pressure plenum 44 todeliver coolant to cooling air plenum 110. Passages in flow conditioningplate 102 may also be in fluid communication with cooling air plenum110.

FIG. 3 is a cross-sectional perspective view of a portion of combustorcap assembly 100 as shown in FIG. 2 (with fuel nozzles 48 removed),according to one or more embodiments of the disclosure, and FIG. 4 is anenlarged partial cross-sectional view of combustor cap assembly 100. Inone embodiment, as shown in FIG. 3, shroud 104 extends axially away froman aft end portion 112 of flow conditioning plate 102. Shroud 104includes a first or forward end portion 114, which is axially separatedfrom a second or aft end portion 116. In one embodiment, as shown inFIG. 3, a flange 118 extends radially inwardly from shroud 104 towardsan axial centerline of shroud 104. In one embodiment, flange 118 isdisposed proximate to first end portion 114. Flange 118 may be used tocouple or connect shroud 104 to a mounting feature (not shown) of flowconditioning plate 102. For example, one or more bolts or other suitablefasteners (not shown) may extend through flange 118 to secure or couplethe two components together.

As shown in FIGS. 3 and 4, combustor cap assembly 100 further includesan impingement plate 120. In one embodiment, impingement plate 120 iscoupled to shroud 104 proximate to second end portion 116. Impingementplate 120 includes a body 121 that extends radially andcircumferentially at least partially across second end portion 116 ofshroud 104. Impingement plate 120 may at least partially define at leastone fuel nozzle passage 122 which extends generally axially therethroughfor receiving fuel nozzle 48 (FIG. 2).

As shown in FIGS. 3 and 4, impingement plate 120 and, more particularly,body 121 thereof, includes a first or upstream side 124. Impingementplate 120 (body 121) also includes a second or downstream side 126.First side 124 of body 121 is configured to be positioned in fluidcommunication with cooling air plenum 110, and second side 126 of body121 is configured to couple in a spaced manner to combustor cap plate140, e.g., via welding. Second side 126 of body 121 and cap plate 140define an impingement air plenum 146 therebetween. Impingement plate 120may further include an outer band portion 128. Outer band portion 128 atleast partially defines a radially outer perimeter of impingement plate120. In various embodiments, as shown in FIGS. 3 and 4, impingementplate 120 and, more particularly, body 121 thereof, at least partiallydefines a plurality of impingement cooling holes 130. Impingementcooling holes 130 extend through first side 124 and second side 126(FIGS. 3 and 4) to provide for fluid communication from cooling airplenum 110 through impingement plate 120 to impingement air plenum 146.

In one embodiment, as shown in FIGS. 3-5, impingement plate 120 furtherdefines at least one cooling flow return passage 132. As illustrated,cooling flow return passage 132 extends through first side 124 andsecond side 126 to provide for fluid communication through impingementplate 120. In one embodiment, cooling flow return passage 132 extendssubstantially axially through impingement plate 120. An inlet 134 tocooling flow return passage 132 is defined along second side 126 ofimpingement plate 120. In one embodiment, a raised portion or area 136of second side 126 surrounds inlet 134. Raised portion 136 is raisedaxially outwardly with respect to the surrounding second side 126.

In particular embodiments, as shown in FIG. 3, outer band portion 128 atleast partially defines a plurality of cooling passages 138 whichextend, in contrast to conventional cooling passages, substantially atan angle relative to a radius R through outer band portion 128 ofimpingement plate 120. Plurality of cooling passages 138 provides forfluid communication out of impingement air plenum 146 in an outwarddirection at an angle relative to a radius R. In this manner, coolingair exiting cooling passages 138 is caused to exit outer band portion128 in an outward direction at an angle relative to radius R to create acooling film over an outer surface thereof. The angle can be any desiredangle to create the desired exiting angle for cooling air 18. In oneoptional embodiment, a greater number of cooling passages 138 may beformed or concentrated proximate to inlet 134 of cooling flow returnpassage 132 than along areas of outer band portion 128 which are notclose to cooling flow return passage 132.

As shown in FIGS. 2, 3 and 4, combustor cap assembly 100 furtherincludes a combustor cap plate 140 (hereafter “cap plate 140”), which iscoupled to impingement plate 120. Cap plate 140 may be coupled, forexample, to outer band portion 128 of impingement plate 120, e.g., viawelding. As shown in FIG. 4, cap plate 140 extends circumferentially andradially across impingement plate 120. As shown in FIG. 3, cap plate 140includes an upstream, impingement side 142, which faces second side 126of impingement plate 120. An opposite or hot side 144 of cap plate 140faces towards combustion zone or chamber 50 (FIG. 2) when installed intocombustor 24. Combustor cap assembly 100 is operatively coupled to fuelnozzle(s) 48. In one embodiment, as shown in FIGS. 3 and 4, cap plate140 further defines fuel nozzle passage 122 through which fuel nozzle 48may extend.

As shown in FIG. 3, and as noted previously, impingement side 142 of capplate 140 is axially spaced from second side 126 of impingement plate120 to define impingement air plenum 146 therebetween. Impingement plate120 and, more particularly, body 121 thereof include a plurality ofimpingement cooling holes 130 (“cooling holes 130” hereafter) therein.Cooling holes 130 provide for fluid communication from cooling airplenum 110 into impingement air plenum 146.

In certain combustors, cooling holes 130 may not provide sufficientcooling to cap plate 140. Notably, certain combustors may provide fluidcommunication out of impingement air plenum 146 that may impact theability of cooling air 18 from cooling holes 130 to efficiently cool capplate 140. For example, in the illustrative combustor shown, coolingpassages 138 provide for fluid communication out of impingement airplenum 146. Also, in the illustrative combustor shown, cooling flowreturn passage(s) 132 provide for fluid communication out of impingementair plenum 146 to at least one upstream element 154 from impingementplate 120. More particularly, as shown in FIG. 3, combustor cap assembly100 may include at least one fluid conduit 148, which is in fluidcommunication with impingement air plenum 146 via cooling flow returnpassage 132. Fluid conduit 148 defines an exhaust passage, which extendsfrom impingement plenum 146 and/or the cooling flow return passage 132,through cooling air plenum 110 and which is fluidly isolated fromcooling air plenum 110.

In various embodiments, as shown in FIG. 3, flow conditioning plate 102is coupled to forward end portion 114 and/or flange 118 of shroud 104and receives cooling air 18 from impingement air plenum 146 via fluidconduit 148 (and annular flow passage 54). While upstream portion 154 isillustrated as including a particular flow conditioning plate 102 (asdisclosed in U.S. Pat. No. 9,964,308), upstream element(s) 154 mayinclude any now known or later developed combustor components that canuse cooling upstream of impingement plate 120. A non-comprehensive listof upstream element(s) 154 may include: flow conditioning plate 102(illustrated), shroud 104, fuel nozzles 48, casing 40, end cover 42,etc.

Normally, cooling holes 130 are generally aligned to focus jets ofcompressed air 18 directly onto impingement side 142 of cap plate 140during operation of combustor 24, thus providing for jets or impingementcooling thereof. However, the various passages (e.g., 132, 138) thatprovide for fluid communication out of impingement air plenum 146 mayprevent some of air 18 from effectively impacting impingement side 142of cap plate 140.

In order to address this situation, in accordance with embodiments ofthe disclosure, cooling tubes 160 (hereafter “tube 160”) extend from atleast a portion of the plurality of impingement cooling holes 130 atsecond side 126 of impingement plate 120. Cooling holes 130 provide forfluid communication between cooling air plenum 110 and impingement airplenum 146 through tubes 160. As shown in FIG. 4, tubes 160 extendpartially towards combustor cap plate 140 through impingement air plenum146 but do not contact impingement side 142 of cap plate 140. In thismanner, tubes 160 ensure more of cooling air 18 impacts impingement side142 of cap plate 140 prior to being fluidly communicated out ofimpingement air plenum 146.

In one embodiment, shown in FIG. 6, tubes 160 are integrally coupledwith impingement plate 120, i.e., with body 121. That is, tubes 160 areformed as extensions of cooling holes 130. Impingement plate 120 withtubes 160 integral therewith can be made using any now known or laterdeveloped manufacturing process such as, but not limited to: additivemanufacture, casting, subtractive machining, etc.

Returning to FIG. 4, in another embodiment, each tube 160 is provided asan insert 162 into a respective cooling hole 130. In this manner, tubes160 provide the same functionality as integral tubes, but the tubes canbe applied to new and already existing impingement plates 120. Inserts162 thus allow application of tubes 160 to older, used impingementplates 120, resulting in improved cap plate 140 cooling in combustioncap assemblies 100 and combustors 24 in which employed. Tubes 160 in theform of inserts 162 can take any form capable of fixed coupling tocooling holes 130.

FIGS. 7-9 show cross-sectional views of a cooling tube 160 in the formof an insert. FIG. 7 is a side view of an insert 162 alone, FIG. 8 is anenlarged cross-sectional view of insert 162 in position in a respectivecooling hole 130 in impingement plate 120, and FIG. 9 is an enlargedcross-sectional view of insert 162 in the process of beinginserted/positioned in a respective cooling hole 130 in impingementplate 120. Each cooling hole 130 has an inner dimension (ID1), at leastnear second side 126 of body 121 of impingement plate 120. Cooling holes130 may have any cross-sectional shape, e.g., circular, polygonal, etc.

Tubes 160 in the form of inserts 162 may include a body 170 having anopening 172 extending longitudinally therethrough. Opening 172 is influid communication with cooling hole 130 and cooling air plenum 110.Opening 172, which has a diameter D, can have any cross-sectional shape,e.g., circular, polygonal, etc. Further, within the limits of arespective cooling hole 130 and body 170 wall thickness, opening 172 canhave any cross-sectional area desired. While FIGS. 4 and 6 illustratetubes 160 with uniform sized openings 172 (that is, openings 172 havinga constant cross-sectional size and shape), tube(s) 160 can haveopenings 172 with different sizes and/or shapes along the length ofopening(s) 172. The shape and/or size of openings 172 can be defined toprovide any impingement cooling desired, i.e., providing customizedcooling, where necessary, to cap plate 140. Opening(s) 172 shape canmatch those of cooling holes 130 or may be different. In someembodiments, a first or first group of inserts 162 may have opening(s)172 with a first size and/or shape, while a second or second group ofinserts 162 may have opening(s) 172 with a second size and/or shape.

Body 170 may also include a discharge end 174 configured for positioningin impingement air plenum 146 and through which opening 172 passes. Inone embodiment, discharge end 174 may include a chamfered surface 176(FIG. 7) to facilitate air flow thereabout, but this is not necessary inall instances. Discharge end 174 includes an outer dimension (OD1)larger than inner dimension (ID1) of a respective cooling hole 130 (nearsecond surface 126 of body 121), i.e., OD1>ID1. In this manner,discharge end 174 limits the extent to which insert 162 can enter arespective cooling hole 130. Discharge end 174 may include a seat 178configured to contact second side 126 of impingement plate 120. A lengthL of discharge end from seat 178 to the terminal end of insert 162 candetermine the extent to which tube 160 traverses impingement air plenum146. The length L can be defined to provide any Z/D factor (FIG. 8) orimpingement cooling desired (where Z is distance from tube 160 toimpingement side 142 of cap plate 140, and D is diameter of opening 172in tube 160). While FIGS. 4 and 6 illustrate tubes 160 with uniformlength, it is emphasized that lengths of tube(s) 160 may vary within aparticular impingement plate 120 to provide customized cooling (e.g.,different Z/D factors), where necessary, to cap plate 140.

Body 170 may also include a flexible insertion end 180 configured forinsertion into a respective cooling hole 130 and a fixation element 182between discharge end 174 and flexible insertion end 180. As will bedescribed, fixation element 182 is configured to fixedly couple tube 160in the respective cooling hole 130. Fixation element 182 has an outerdimension OD2 that is configured to create an interference fit 184 withinner dimension ID1 of respective cooling opening 130 (shown enlarged inFIG. 8). As used herein, “interference fit” can include any now known orlater developed fastening between two tight fitting and mating partsthat creates a joint held together by friction once the parts areplaced/forced together, e.g., press fit, friction fit, bonded fit,bonded press fit, bonded shrink fit (at least one part heated), etc.

Flexible insertion end 180 may include a retention element 186 having anouter dimension OD3 that is larger than outer dimension OD2 of fixationelement 182 and inner dimension ID1 of respective cooling hole 130.Flexible insertion end 180 also includes at least one flexing feature190 configured to allow flexing of retention element 186 as it passesthrough inner dimension ID1 of cooling opening 130 in an insertiondirection (downwardly as shown). Retention element 186 is otherwiseconfigured, e.g., shaped and/or sized, to prevent removal thereof frominner dimension ID1 of cooling opening 130 once insert 162 is insertedin the opening. Flexing feature(s) 190 allows flexing of retentionelement 186 between, as shown in FIG. 8, a relaxed position having outerdimension OD3, and as shown in FIG. 9, an inwardly flexed positionhaving a flexed, outer dimension OD4 that is temporarily smaller thanouter dimensions OD1 and OD2 of body 121 and inner dimension ID1 ofrespective cooling hole 130.

Flexible insertion end 180 can also optionally include a tapered distalend 192, e.g., to assist insertion into cooling opening 130. Flexingfeature(s) 190 can take any form of structure allowing distal end 192 toflex, making an outer dimension OD4 small enough to pass through innerdiameter ID1 of cooling opening 130. In one non-limiting example, aflexing feature 190 may include at least one slot 194 extending througha wall of body 170, longitudinally from distal end 192 of flexibleinsertion end 180. Any number of slots 194 may be employed, e.g., a pairof diametrically opposing slots (shown), two pairs of diametricallyopposing slots, an odd number of circumferentially spaced slots, etc. Inthis manner, insert 162 can be readily inserted into respective coolinghole 130 and prevented from removal from cooling opening 130 byretention feature 186 if ever interference fit 184 fails.

Insert 162 may include any now known or later developed material capableof withstanding the environmental conditions of combustor 24. In onenon-limiting example, insert 162 may include the same material asimpingement plate 120, such as, but not limited to, a nickel or cobaltbased superalloy or a stainless steel. Similarly, where tubes 160 areintegral with impingement plate 120, they can be made of the samematerial as the impingement plate.

The dimensions described herein can take any of a variety of formsdepending on the cross-sectional shapes of cooling holes 130, tubeinsert 162, etc. In certain embodiments, as shown in FIG. 4, coolingholes 130 and tube inserts 162 are circular, making the relevantdimensions diameters of the respective structures. It will be readilyrecognized that the dimensions can be widths where the structures haveother cross-sectional shapes, e.g., ovals/ellipsoid, polygon, etc.

In FIG. 4, every cooling hole 130 is illustrated as including arespective tube 160. However, as illustrated in FIG. 6, not everycooling hole 130 requires a tube 160. In accordance with embodiments ofthe disclosure, tubes 160 can be used wherever necessary to create thecooling required. Accordingly, in certain embodiments, some coolingholes 130 may not have a tube 160. Similarly, while cooling holes 130are shown all with the same inner dimension, cooling holes 130 and/ortubes 160 may have different dimensions within a particular impingementplate 120, e.g., the inner dimension of each can vary across impingementplate 120 to provide more or less cooling air 18 in desired locations tocustomize the cooling. In addition, as noted herein, a length L thatdischarge end 174 of tube 160 extends from second side 126 ofimpingement plate 120 (and related Z/D factor) may vary across theimpingement plate 120 to provide the desired cooling where necessary.

Referring to FIG. 10, alternative embodiments of an impingement plate120 and a tube 260, in the form of an insert 262, are illustrated. Inthis embodiment, each of the at least a portion of plurality ofimpingement cooling holes 130 includes a tube retention seat 200 atfirst side 124 of impingement plate 120. Also, in this embodiment, abody 270 of insert 262 is configured for positioning in a respectiveimpingement cooling hole 130 and has opening 172 extendinglongitudinally therethrough. Tube 260/insert 262 extends throughimpingement cooling hole 130 with a clearance fit 284. That is, outerdimension OD5 of insert 262 has a clearance fit with inner diameter ID1of impingement cooling opening 130, OD5<ID1. A discharge end 274 ofinsert 262 is configured for positioning in impingement air plenum 146but is devoid of seat 178 (FIG. 8).

Body 270 also includes a fixation collar 202 opposite discharge end 274.Fixation collar 202 extends radially from a fixation end 210 of body270. Fixation collar 202 is configured to matingly couple body 270 intube retention seat 200. In this embodiment, a tube retention element220 is coupled to first side 124 of body 121 of impingement plate 120,e.g., by fasteners or welding. Tube retention element 220 fixedly holdsfixation collar 202 in tube retention seat 200, which holds each tube260 in position with discharge end 274 disposed in impingement airplenum 146. Tube retention element 220 may include any member capable ofretaining fixation collar(s) 202 in tube retention seat(s) 200.

In one non-limiting example, tube retention element 220 includes aperforated metal plate with a plurality of openings 222 co-axiallyaligned with cooling holes 130 of impingement plate 120. Specifically,each opening 222 of tube retention element 220 is in fluid communicationwith cooling air plenum 110 and opening 172 in body 270 of tube 260,thus allowing coolant to pass from cooling air plenum 110 through tuberetention element 220 and through tube 260 to impingement air plenum146. Each opening 222 is sized appropriately, such that a perimetersurface 224 of opening 222 engages fixation collar 202, thus preventingremoval of tube 260 from impingement plate 120. Any number of tuberetentions seats 200 and openings 222 may be provided in impingementplate 120 and tube retention element 220, respectively.

Returning to FIGS. 4 and 6, in operation, a method according toembodiments of the disclosure may include communicating cooling air 18from cooling air plenum 110 through impingement plate 120 that definescooling holes 130 therein. As noted, first side 124 of impingement plate120 is in fluid communication with cooling air plenum 110. The methodmay also include directing cooling air 18 through tubes 160 extendingfrom at least a portion of cooling holes 130 at second side 126 ofimpingement plate 120 toward combustor cap plate 140. Hence, embodimentsof the disclosure provide tubes 160 to impingement plate 120 to allowmore precise and closer delivery of cooling air 18 to combustor capplate 140. The tubes may be integrally formed with impingement plate120, or they can be provided as inserts 162 so they can be applied toexisting impingement plates 120.

Approximating language, as used herein throughout the specification andclaims, may be applied to modify any quantitative representation thatcould permissibly vary without resulting in a change in the basicfunction to which it is related. Accordingly, a value modified by a termor terms, such as “about,” “approximately” and “substantially,” are notto be limited to the precise value specified. In at least someinstances, the approximating language may correspond to the precision ofan instrument for measuring the value. Here and throughout thespecification and claims, range limitations may be combined and/orinterchanged; such ranges are identified and include all the sub-rangescontained therein unless context or language indicates otherwise.“Approximately” as applied to a particular value of a range applies toboth end values and, unless otherwise dependent on the precision of theinstrument measuring the value, may indicate+/−10% of the statedvalue(s).

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present disclosure has been presented for purposes ofillustration and description but is not intended to be exhaustive orlimited to the disclosure in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the disclosure. Theembodiment was chosen and described in order to best explain theprinciples of the disclosure and the practical application and to enableothers of ordinary skill in the art to understand the disclosure forvarious embodiments with various modifications as are suited to theparticular use contemplated.

What is claimed is:
 1. A combustor cap assembly, comprising: animpingement plate defining a plurality of impingement cooling holes,wherein a first side of the impingement plate is in fluid communicationwith a cooling air plenum; a combustor cap plate coupled to theimpingement plate, wherein the combustor cap plate and a second side ofthe impingement plate define an impingement air plenum therebetween; andtubes extending from at least a portion of the plurality of impingementcooling holes at the second side of the impingement plate and extendingpartially towards the combustor cap plate through the impingement airplenum; wherein each tube includes a body having a central openingextending longitudinally therethrough, the body further including: adischarge end positioned in the impingement air plenum, a flexibleinsertion end inserted into a respective impingement cooling hole of theplurality of impingement cooling holes, a fixation element between thedischarge end and the flexible insertion end, the fixation elementhaving a first outer dimension that is fully annular andcircumferentially solid about a length of the fixation element, whereinthe first outer dimension of the fixation element and an inner dimensionof the respective impingement cooling hole create an interference fit tofixedly couple each tube in the respective impingement cooling hole ofthe at least the portion of the plurality of impingement cooling holes,wherein each tube provides for fluid communication between the coolingair plenum and the impingement air plenum through the central opening ofeach tube and the respective impingement cooling hole; and wherein theflexible insertion end includes: a retention element having a secondouter dimension that is larger than the first outer dimension of thefixation element and the inner dimension of the respective impingementcooling hole, at least one flexing feature configured to allow flexingof the retention element between a relaxed position having the secondouter dimension and an inwardly flexed position having a flexed, outerdimension that is temporarily smaller than the first and second outerdimensions and the inner dimension of the respective impingement coolinghole, and wherein the at least one flexing feature includes at least oneslot extending longitudinally through a wall of each tube from a distalend of the flexible insertion end.
 2. The combustor cap assembly ofclaim 1, wherein the flexible insertion end includes a tapered distalend.
 3. The combustor cap assembly of claim 1, wherein the discharge endhas a chamfered surface.
 4. The combustor cap assembly of claim 1,wherein the discharge end includes a third outer dimension larger thanthe inner dimension of the respective impingement cooling hole of theplurality of impingement cooling holes and a seat configured to contactthe second side of the impingement plate.
 5. The combustor cap assemblyof claim 1, wherein the impingement plate further includes an outerband, wherein the outer band defines a plurality of cooling passagescircumferentially spaced along the outer band, wherein the plurality ofcooling passages provides for fluid communication out of the impingementair plenum in an outward direction at an angle relative to a radius. 6.The combustor cap assembly of claim 1, wherein the impingement platedefines a cooling flow return passage in fluid communication with theimpingement air plenum, the cooling flow return passage in fluidcommunication with at least one upstream element from the impingementplate.
 7. A combustor, comprising: a combustor cap assembly operativelycoupled with a fuel nozzle, the combustor cap assembly including: animpingement plate defining a plurality of impingement cooling holes,wherein a first side of the impingement plate is in fluid communicationwith a cooling air plenum; a cap plate coupled to the impingement plate,wherein the cap plate and a second side of the impingement plate definean impingement air plenum therebetween; and tubes extending from atleast a portion of the plurality of impingement cooling holes at thesecond side of the impingement plate and extending partially towards thecap plate through the impingement air plenum; and the fuel nozzleextending through the combustor cap assembly, wherein each tube includesa body having a central opening extending longitudinally therethrough,the body further including: a discharge end positioned in theimpingement air plenum, a flexible insertion end inserted into arespective impingement cooling hole of the plurality of impingementcooling holes, a fixation element between the discharge end and theflexible insertion end, the fixation element having a first outerdimension that is fully annular and circumferentially solid about alength of the fixation element, wherein the first outer dimension of thefixation element and an inner dimension of the respective impingementcooling hole create an interference fit to fixedly couple each tube inthe respective impingement cooling hole of the at least the portion ofthe plurality of impingement cooling holes, wherein each tube providesfor fluid communication between the cooling air plenum and theimpingement air plenum through the central opening of each tube and therespective impingement cooling hole; and wherein the flexible insertionend includes: a retention element having a second outer dimension thatis larger than the first outer dimension of the fixation element and theinner dimension of the respective impingement cooling hole; and at leastone flexing feature configured to allow flexing of the retention elementbetween a relaxed position having the second outer dimension and aninwardly flexed position having a flexed, outer dimension that istemporarily smaller than the first and second outer dimensions and theinner dimension of the respective impingement cooling hole, and whereinthe at least one flexing feature includes at least one slot extendingthrough a wall of each tube longitudinally from a distal end of theflexible insertion end.
 8. The combustor of claim 7, wherein thedischarge end includes a third outer dimension larger than the innerdimension of the respective impingement cooling hole of the plurality ofimpingement cooling holes and a seat configured to contact the secondside of the impingement plate.
 9. The combustor of claim 7, wherein theimpingement plate further includes an outer band, wherein the outer banddefines a plurality of cooling passages circumferentially spaced alongthe outer band, wherein the plurality of cooling passages provides forfluid communication out of the impingement air plenum in an outwarddirection at an angle relative to a radius.
 10. The combustor of claim7, wherein the impingement plate defines a cooling flow return passagein fluid communication with the impingement air plenum, the cooling flowreturn passage in fluid communication with at least one upstream elementfrom the impingement plate.